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Differential and selective media for the faecal streptococci
Author(s) -
Barnes Ella M.
Publication year - 1959
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740101204
Subject(s) - sodium azide , agar , isolation (microbiology) , food science , microbiology and biotechnology , biology , starter , bacteria , chemistry , biochemistry , genetics
Both sodium azide and thallous acetate have been incorporated separately in media for the selective isolation of the faecal streptococci (Lancefield group D). It has been found that the various methods developed for increasing the selectivity of the sodium azide media often eliminate Str. bovis. the importance of this in relation to these organisms as indicators of faecal pollution in water and foods is discussed. By the addition of tetrazolium to the thallous acetate agar at pH 6.0, it is possible to distinguish colonies of Str. faecalis and variants zymogenes and liquefaciens from Str. faecium and Str. durans. This method has been used for determining the numbers and types of faecal streptococci in the intestines of the various meat animals and poultry and to show changes in species following antibiotic feeding.